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Coronary flow reserve in hypertrophic obstructive cardiomyopathy assessed by intracoronary Doppler catheter
Jens Litmathe1, Daniel Stosch, Hans G Klues
1Department of Thoracic- and Cardiovascular Surgery, Heinrich-Heine-University, Düsseldorf, Germany. litmathe@med.uni-duesseldorf.de
Insights
Coronary flow reserve in hypertrophic obstructive cardiomyopathy (HOCM) patients was assessed and found to be normal. However, a retrograde coronary flow was detected in most patients, suggesting potential microcirculation changes.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Hypertrophic obstructive cardiomyopathy (HOCM) presents significant challenges despite advances in diagnosis and treatment.
- The pathophysiology of coronary circulation in HOCM is not fully understood.
Purpose of the Study:
- To evaluate the coronary flow reserve in patients with HOCM.
Main Methods:
- 15 HOCM patients without coronary artery stenosis underwent assessment.
- Intracoronary Doppler catheter used to measure average peak velocity and absolute coronary flow reserve in LAD and Cx arteries.
- Pharmacological agents (papaverine, substance P) and pacing were employed for stress.
- Coronary square plane calculated, and retrograde coronary flow examined.
Main Results:
- Pharmacological stimulation yielded higher average peak velocities than pacing.
- Retrograde flow observed in 8/10 LAD and 3/8 Cx arteries.
- Coronary flow reserve was greater during pharmacological stress compared to pacing.
- No correlation found between coronary square plane increase and coronary flow reserve.
Conclusions:
- Coronary flow reserve was not decreased in HOCM patients.
- The findings do not rule out ischemia due to altered microcirculation.
- Retrograde coronary flow was a common finding in the study cohort.
Background:
In spite of progress in diagnosis and treatment, hypertrophic obstructive cardiomyopathy (HOCM) remains a serious medical problem. Among many issues, the pathophysiology of the coronary circulation in HOCM has not yet been fully examined.
Aim:
To assess coronary flow reserve in HOCM.
Methods:
The study group consisted of 15 patients (6 males, 9 females, mean age 51+/-15 years) with typical echocardiographic signs of HOCM and without stenosis of the coronary arteries. Using an intracoronary Doppler catheter, the average peak velocity and the absolute coronary flow reserve were determined in the proximal, medial and distal parts of the left anterior descending (LAD) and the circumflex coronary artery (Cx) following administration of papaverine, substance P, and during pacing. The coronary square plane was calculated angiographically after substance P injection. The retrograde coronary flow and the relationship between the increase of the coronary square plane and the coronary flow reserve were also examined.
Results:
Under pharmacological stimulation, higher values of the average peak velocity were observed compared to pacing. A retrograde flow was observed in 8 of 10 patients in the LAD and in 3 of 8 patients in the Cx. The coronary flow reserve was higher under pharmacological stress than during pacing. No relationship was found between the increase of the coronary square plane and the coronary flow reserve.
Conclusions:
No decrease in the coronary flow reserve was observed in our patients with HOCM which, however, does not exclude the possibility of ischaemia based on subordinate vessels and microcirculation changes. In the majority of patients a retrograde flow was detected.
